The man, referred to only as "Mr T", was detained in Villawood detention centre in Sydney three times over four years, in one case for up to eight months.

Mr Beazley says the department needs to be fully investigated.

"This department can not be micro-managed out of its problems," he said.

"This department has to undergo a full-scale royal commission to tell us what has gone wrong with it, how many Australians have been mistreated by it, how many people who are not Australians have been mistreated by it."

This blog has been calling for a Royal Commission into mandatory detention from its outset. It is the only way the truth will be revealed and responsibility for this abusive system properly apportioned.